Our long-range goal is to improve the therapy of Myeloma. The central hypothesis for the proposed research is that inhibition of specific gene targets will modulate the sensitivity of Myeloma cells to bortezomib and other proteasome inhibitors. Our objective in this proposal is to apply advanced functional genomic strategies to identify and rapidly validate the critical role of candidate genes in drug performance and advance this information clinically. Specific Aim 1 will address the influence of recently-identified promiscuous mutations of NFKappaB in Myeloma and their relationship to proteasome inhibitor sensitivity. Aim 2 will utilize an innovative high-throughput siRNA screen to identify critical genes or pathways which sensitize or protect Myeloma cells from bortezomib- or PR-171-induced cell death. A library of 10,000 siRNA targeting the druggable genome will be applied. Specific Aim 3 is structured to enable rapid validation of the hypothesis that the candidate genes prioritized in Specific Aim 2 are functionally relevant as sensitizing targets in Myeloma cells. In Specific Aim 4, we will use tissues and genetic data from clinical trials and clinical databases to rapidly validate the clinical importance of prioritized candidates, and previously-described targets of bortezomib. The ultimate goal of our entire study will be to generate new sensitizer drugs to be used in combination therapy to increase the clinical success rate of bortezomib or other PI therapy.